Multi-Fuel Engine Injection for Stable Low-GHG Idle Operation

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Solution Overview

Problem

Existing engine devices face increased production costs and reduced rotational stability due to the application of common rail systems for both main and auxiliary fuels, limiting the use of low GHG fuels like ammonia or alcohol, especially during idle and low load operations.

Innovation Solution

The engine device employs a main fuel injection unit controlled by electric means and an auxiliary fuel injection unit by mechanical control, with a control device managing injection parameters to optimize the use of low GHG fuels like ammonia or alcohol, while suppressing cost increases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a common rail system is applied to supply both main fuel and auxiliary fuel, then injection control flexibility and rotational stability are improved, but product cost increases

Engineering Contradiction:
Improverotational stabilityVSAvoidproduct cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The fuel supply system is segmented into two independent paths: a common rail system for auxiliary fuel injection and a mechanically controlled injection device for main fuel injection. This segmentation allows each subsystem to be optimized for its specific function while avoiding the need to implement an expensive common rail system for both fuel types, thereby reducing overall product cost while maintaining rotational stability through precise auxiliary fuel control

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mechanically controlled injection device is designed to handle main fuel injection with capabilities typically associated with common rail systems, while the common rail system provides supplementary fuel injection. This multi-functional approach allows the simpler mechanically controlled device to perform primary injection functions, reducing the need for expensive common rail infrastructure while maintaining overall system performance and rotational stability

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If a mechanically controlled injection device is applied to supply main fuel, then product cost is reduced, but injection pressure and flexibility are lowered

Engineering Contradiction:
Improveproduct costVSAvoidinjection pressure
Core Design Contradiction:
Ease of manufactureVSStress or pressure

Solution Approach 1:

The common rail system acts as an intermediary component that receives auxiliary fuel and stores it under high pressure, then delivers it to the combustion chamber. This intermediary high-pressure auxiliary fuel injection compensates for the lower injection pressure of the mechanically controlled main fuel injection device, ensuring adequate atomization and combustion performance while maintaining cost effectiveness

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the pressure parameters of auxiliary fuel through the common rail accumulation mechanism, storing fuel at high pressure and delivering it at controlled rates. This parameter change in auxiliary fuel pressure compensates for the inherently lower pressure capability of mechanically controlled injection, maintaining overall injection effectiveness without requiring expensive high-pressure mechanical injection systems

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If a mechanically controlled injection device is applied to supply main fuel, then product cost is reduced, but flexibility in changing injection timing is lowered

Engineering Contradiction:
Improveproduct costVSAvoidinjection timing flexibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The system implements dynamic control by allowing the common rail system to adjust auxiliary fuel injection timing and quantity independently of the mechanically controlled main fuel injection. This dynamic adjustment capability compensates for the fixed timing characteristics of mechanical injection, enabling the system to adapt to varying load conditions and maintain optimal combustion timing flexibility without requiring expensive electronically controlled mechanical injectors

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The common rail system performs periodic auxiliary fuel injections that supplement the main fuel injection cycles. By controlling the frequency and timing of these periodic auxiliary injections, the system achieves flexible adaptation to different operating conditions, effectively compensating for the limited timing flexibility of the mechanically controlled main fuel injection while maintaining cost effectiveness

Inventive Principle:
Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration allows stable idle and low load operations with low GHG fuels, reducing greenhouse gas emissions and maintaining engine performance without excessive cost, enhancing atomization and penetration of the main fuel.

Implementation Method 1

a main fuel injection unit that injects the main fuel by electric control

Methodology Applied
Scientific EffectElectric control:

Implementation Method 2

an auxiliary fuel injection unit that injects the auxiliary fuel by mechanical control

Methodology Applied
Scientific EffectMechanical control:

Implementation Method 3

enhancing atomization and penetration of the main fuel

Methodology Applied
Scientific EffectAtomization:

Implementation Method 4

an engine device including an engine that is operated by burning a main fuel including a low GHG fuel

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4624737A1Engine device
Publication Date: 2025.10.01 YANMAR HLDG CO LTD
  • EP4624737A1 patent drawingFigure 1
  • EP4624737A1 patent drawingFigure 2
  • EP4624737A1 patent drawing

AI summary

[Problem] To provide an engine device that includes an engine capable of performing idle operation and low load operation with a main fuel including a low GHG fuel, which emits less greenhouse gas, while suppressing an increase in product costs. [Solution] The engine device 1 including a multi-fuel engine 2 that is operated by burning a main fuel including a low GHG fuel, which emits less greenhouse gas than a petroleum-based fuel, and a hydrocarbon-based auxiliary fuel includes a main fuel injection unit 7a of a fuel injection unit 7, which injects the main fuel by electric control, an auxiliary fuel injection unit 7b of the fuel injection unit 7, which injects the auxiliary fuel by mechanical control, and a control device 8 that electrically controls at least one of the injection volume, injection pressure, injection timing, and injection frequency of the main fuel by the main fuel injection unit 7a. The control device 8 controls the rotation speed of the multi-fuel engine 2 at the time of idle operation.